Scoping analysis on core explosion and energy release of liquid metal fast reactor during core meltdown severe accident

摘要

A numerical analysis is conducted to estimate the energy release and core expansion behavior induced by a core meltdown severe accident in a sodium cooled fast reactor. An analysis of the CDA energy release based on the Bethe-Tait method is carried out and its results are used as the initial conditions for the core explosion computations. Calculations are made for the super prompt power excursions of a KALIMER-150 core and the influences of the Doppler effect on the power excursions are investigated. The transient pressure, temperature and expansion of the core are examined by solving the equation of state of ideal gas and nonlinear governing equation of momentum conservation in one-dimensional spherical coordinates. Energy balance is examined during the core expansion process. Heat transfer between the core and surrounding medium as well as bubble rise during the expansion process is briefly investigated.